Serpent's Tooth
by hiddenhibernian
Summary: There is no mercy for traitors, no peace for the wicked. Bellatrix will see to that. A/U


**Thanks very much to my fantastic beta, Lokilette! Any mistakes are my own, do feel free to point them out if you spot any...**

* * *

There were many ways to die in that first war. This is how it could have gone, had things been different:

 **-oOo-**

"This is what you choose?" she asked, knowing the answer but not quite able to make herself believe it.

"This is what I choose." Wisps of dark hair fluttered in the wind, framing his pale face like a dirty halo. His eyes shone brightly, like he'd found his path at last, and she could barely bear to look at him.

"Then you're an idiot." She'd even offered to _help_ him, giving him the chance to renounce his folly despite knowing she would be betraying her lord and master in turn by concealing his wavering. Yet, Regulus was determined to throw away his birthright and his future.

"You won't give me away, will you?" The pleading look in his eyes had served him well; it had got him out of trouble ever since he'd been a plump-cheeked child wobbling after his older cousins, not quite able to keep up with them but determined not to be left out. Regulus had always been the youngest and weakest, relying on the goodwill of his older cousins to wait for him, to give him a part in their games and to take the blame when they were found out.

It was so like him to treat being a Death Eater like another game, a dress-up cloak he could discard whenever he chose. For Regulus, consequences happened to other people.

"I won't." The lie fell easily from her lips, perhaps because her first instinct had been to protect him. They weren't children any longer, though, and Bellatrix was long done rescuing Regulus from trouble of his own making.

She had sworn oaths, too, and she intended to keep them.

* * *

The next time she saw her cousin was in the presence of the Dark Lord. Regulus was dirty and dishevelled, and there was an ugly bruise on his chin. Even though he tried to look unconcerned, raising his head to look into the eyes of the blank masks surrounding him, she could see his hands shaking.

He'd never looked more like his brother than he did now, wearing his desperate bravery on his sleeve, and Bellatrix felt a rush of hatred towards her blood traitor cousin. If Sirius had been where he should have been, by the Dark Lord's side, Regulus would never have thrown his life away in this way.

When Sirius got his claws into someone they'd do anything to get his approval, to see that easy smile turned to them. It was easy to be seduced by his careless charm, but Bellatrix had seen Sirius for what he was for many years now. She should have destroyed him long ago; that way, he couldn't have dragged his brother down with him.

Regulus had been thrown in a heap before the feet of their Master, surrounded by a circle of the faithful. All he would be able to see was the masks and black cloaks, but from her higher vantage point, Bellatrix could pick out familiar figures by their height and mannerisms. A stray strand of blond hair escaping from the hood announcing Lucius' presence; next to him, a thin set of shoulder and a permanently straightened back suggested Snape. He always looked smaller in formal attire than his own robes; perhaps it was the half-blood shining through.

Her Master spoke softly, but all of them who bore his mark felt the icy trickle of his anger down their spines. "You're of noble stock, and yet there must be something rotten in the House of Black since you betrayed me. I wonder what it is?"

Regulus stared into his eyes, showing how little respect he had for the Master he'd sworn allegiance to, but said nothing.

What happened next took everyone by surprise; even the Dark Lord flinched slightly. Regulus suddenly seized up, doing his best to fold into two despite almost being strangled by his chains. He made a horrible, wheezing sound. Lucius forced his face upwards – it was blue and distorted by convulsions, almost as if he was being strangled by an invisible coil. There was a bubbling noise from his throat, and he emptied the contents of his stomach on Lucius' new dragon hide boots.

Then, his whole body slackened.

Regulus Arcturus Black had died in less than ten seconds, taking his secrets with him. The little weasel must have poisoned himself when he'd been captured; it was just his luck that the effects had kicked in just before he was about to suffer the consequences for his treachery. Bellatrix didn't waste any tears on him; traitors got what they deserved, and the moment Regulus decided to deceive the Dark Lord he must have realised that his fate was inevitable. He was just one of many.

* * *

All had been lost, so it barely mattered anymore.

Still, she was relieved Cissy escaped Azkaban. It was, however, a surprise not to find Lucius in the little group of bedraggled convicts in tattered robes disembarking on the windswept rock. His devotion had been put on the scales and found wanting; Bellatrix should have known better than to trust a Malfoy to stay faithful to anything but themselves. Their rise from the worst kind of rabble coming to England in the wake of William the Bastard to their current illustrious position spoke for itself.

At least Lucius wasn't family. As the years wore on and Azkaban stole what remained of her beauty, she started doubting even those dearest to her. Almost all the Blacks had betrayed her – Andromeda and Sirius and Regulus. Even Uncle Alphard, staunchly pure-blood in life, had shown his true colours when he died.

It was only after her Master's return she discovered why Regulus had decided to sell his life so cheaply, instead of prospering on the side of the Dark Lord. She was going through her aunt's papers, a task that had been waiting for more than a decade due to both sons having disqualified themselves from carrying out any familial duties, when she came across a letter from Regulus.

At first she was pleased to see her cousin's almost childish handwriting – the loose loops reminded her of birthday party invitations and letters from Hogwarts.

Then she was horrified.

Regulus hadn't been fool enough to put the details of his betrayal into words, but interspersed between abject apologies from the son who always thought he'd be forgiven anything ("I know you'll be disappointed, Mother, but –") and ridiculous boasts ("I will make sure the Dark Lord remembers me") there were enough clues to piece it together.

The Master had incurred Regulus' displeasure by dispensing with some Muggle children he'd deemed surplus to requirements. The urchins had been playing in a disused quarry they'd used for a Dark Revel, only to be found mid-ceremony when one of them squealed so loud the whole countryside would have heard if it hadn't been for Yaxley's Silencing Charms.

There had been pain before they were sniffed out, and screaming. Regulus claimed to still hear weeks later. Despite having been taught all his life that Muggles were worth little more than animals, he still hadn't been able to watch them suffer with equanimity. The memory had eaten away at him, wormed its way into his heart until it had ground down his sense of duty and his pride and reduced him to nothing more than a blood traitor.

Regulus, however, had been a traitor with a plan.

The letter didn't specify what he'd been planning to do, other than that he'd decided to attempt something spectacular (at least he'd had a proper lack of modesty). Bellatrix could only be grateful that he'd confided in her before carrying out whatever he'd been planning. Surely the Dark Lord would have found out otherwise?

Bellatrix burnt the letter as soon as she'd read it. She couldn't afford to give her Master another reason to distrust her. With Sirius on the loose and her mongrel niece running with a werewolf, Regulus bringing more shame on her than he already had was more than she could bear. Knowing her Aunt Walburga, Bellatrix suspected she'd held on to the letter as a remembrance of sorts – a reminder that her second son had been as useless as the first.

Bellatrix didn't need any mementos. As she watched the edges of the letter wither in the heat of the fire she'd conjured, she swore never to be as weak as her cousin had been. Even wizarding children grew up to be blood traitors; just look at Sirius. She'd do whatever it took to rid the world of the unworthy, regardless of the price.

Harry Potter and his little friends were just the beginning.

* * *

They met again beyond the veil – all of them, even Sirius. No matter how it began, the end was always the same. Whether he'd died in a lake crawling with dead bodies or at the feet of the Dark Lord, Regulus never met Bellatrix' eyes. He was looked towards his magnificent brother, who faced her in turn.

Bellatrix approached them with her usual confidence that faltered and died beneath Sirius' stare. She didn't know how it was, but somehow all her choices didn't seem so clear-cut here. She knew she had to stand with them, all the Blacks together, but the brothers kept as much distance as possible between them.

By then, they knew there was a price to pay for anyone who accepted the thirty pieces of silver, whether their betrayal was for the sake of glory or spite or the greater good.

They were meeting for the reckoning, and Bellatrix was beginning to understand that she didn't know the rules anymore.

 **-oO THE END Oo-**


End file.
